This invention relates to fire-retardant putty-like compositions for filling the spaces in bores penetrating walls and floors of buildings and having electric wires and cables extending therethrough or for filling the clearances at the joints of interior finishing materials of buildings.
Various fire-retardant putty-like compositions of this type have heretofore been proposed. These compositions must have such properties that when a fire breaks out in a section of a building, the composition, exposed to a high temperature in the initial stage of the fire, will not sag due to softening and deformation per se or fall in molten drops, without permitting flames and smoke to spread to an adjacent section through a space which would otherwise be formed. Additionally the putty-like composition must remain in shape free of large deformation or dripping even if heat and wind pressure build up in the fire section due to fierce flames and heavy smoke amidst of the fire. It is further desired that even when the composition has been burned out, carbonized and eventually ashed, the residual ashed product has toughness without becoming brittle and falling, thus completely preventing the spread of fire to the adjacent section to minimize the damage.
Published Unexamined Japanese Patent Application No. 122895/1977 discloses a composition containing soybean oil as a binder and consisting mainly of an inorganic filler such as hydrated alumina and an inorganic fiber such as asbestos. The composition softens and deforms with a rise in temperature in the event of a fire, is not satisfactory in non-sagging properties and fails to fully prevent the spread of fire. Published Unexamined Japanese Patent Applications Nos. 34150/1978 and 125552/1977 disclose compositions containing liquid chloroprene as a binder and consisting predominently of an inorganic filler such as hydrated alumina, and glass fiber or like inorganic fiber or an organic fiber. Although having good non-sagging or non-dripping properties, the compositions burn when subjected to a fierce fire involving a heavy smoke and high wind pressure, giving a brittle ash residue which cracks and progressively breaks down into falling fragments to form a hole where the composition has been applied. Thus the compositions are unable to completely prevent the spread of fire.
While the putty-like compositions of this invention comprise known materials which are individually employed in the prior art references mentioned above, the materials are used in specified combination in specific proportions as will be described later, so that the present compositions exhibit outstanding performance, have excellent non-sagging and non-dripping properties under the sever conditions of fires and retain the original shape, or a shape near to the original even when burned to an ashed state because the ash residue has exceedingly high toughness which has never been afforded by the conventional putty-like compositions. The present compositions therefore assure outstanding smoketightness and effectively prevent the spread of fire. Needless to say, the compositions are easy to handle especially for filling spaces.